Method of forming projections.



G.' c. KNAUFF. METHOD OPPORMING PROJECTIONS.

APPLICATION FILED AUG. 17' |912.

1,142,82, Patented June 15, 1915.

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y George .y

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y G. C. KNAUFF.

METHOD 0F F'ORMING PROJECTIONS.

APPLICATION FILED A I |912 1,142,820, l Patented June 15, 1915.

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i 66mg@ l I ist GEORGE C. KNAUFF, 0F CHICAGO, ILLINOIS.

METHOD 0F FRMING' PBOJ'ECTIOVNS..

annesso.

Specification of Letters Patent.v

Patenten .rune 15,1915.

. Application led August 17, 1912. Serial No. 715,607.

To all whom. t may concern.'

Be it known that I, GEORGE C. KNAUFF, a citizen of the United States, residing at Chicago, in the county of Cook and State of lllinois, have invented a certain new and useful improvement in Methods of Forming Projections, of which the following is a full, clear, concise, and exact description, reference being had to the accompanying drawings, forming a part of this specification.

My invention relates to processes or methods for forming raised portions or projections upon I.the surface of materials, its object being to obtain a secure and rigid fastening for the material of 4which each projecting part is made, without the use of cement or of any auxiliary retaining member; also to secure anexact and unchangeable distance between the exposed tip of the projecting material and the surface from which this material projects.

My invention is particularly applicable to the construction of articles made in part of hard rubber, as fory instance, in forming the projections which serve as anchoring elements upon the rubber plugs, used with' automobile lighting sockets. In securing such projection-forming pins to the rubber bodies, it has vheretofore been customary 4either to cement them in place, or to deand is particularly adapted for forming metal projections of a slight but denitely predetermined height upon a member of in-v sulating material. lt is shown in this application in the accompanying drawings, iny

which Figure 1 shows anelevation of anattachment plug before the insertion of the metal member.v which is to form projections upon the plug at both ends, a part vof the. plug being cut away to show a section o f theinterior. Fig. 2 shows' an elevation of the metal proj ection-forming member before insertion. Fig. 3 shows a partial sectlon of the, plug with this metal'member united to 1t but not yet out oft' at its ends. Fig. ,4i

shows an alternative form of metal member. I

Figs. 5 and 6 are sections along lines 5-'-5 and 6--6 in Fig. 4. Fig. 7 shows a partial section of a plug with perforations passing part way through the same for receiving projection-forming materials. Fig. 8 shows a metal projection formed upon a rubber plate by my process. Fig. 9 shows the method of inserting thev metal projectlon-forming member shown in Fig. 2 in the plug shown in Fig. 1. Fig. 10 shows the method of cutting off the surplus length close to its boiling point (or to about 205 degrees Fahrenheit), thereby softening the surface portions of the rubber, including. -the wall ofl the perforation. I then grasp one end Fof the member D between the jaws of the chuck Gr of a. drill press H .as shown in Fig. 9 and rotate the chuck while the body B is kept from turning by resting in a non-rotatable grooved supportI I. On raisingthis support while the member D is being rotated, the thread E Vcompresses the softened portions of the rubber body B adjoining the erforation, thereby allowing the member` .y tothread its way through the bodyB. Then, when the assembled parts B and D are allowed to cool, thecompressed portions of the .rubber endeavor to resume their original. volume, thereby gripping the surface of the thread E so tightly s that I have found it impossible to movethe member D with reference to the, body B so as to alter the distance to which the ends of the former ro'ect.

The lengt o the threaded portion of the member at each end of the perforation will contact with unthreaded portions of the inserted member. Consequently, when the perforated material hardens, it will form contracted portions around the inserted material at each end of the perforation, which portions will act as'stops to prevent the unscrewing of the inserted member.

In carrying out my process, I preferably give the member of which the projections are to be formed a cylindrical form, and roll raised threads upon the same. However, I have found that instead of rolling the thread upon this member, the central portion of the insertible member may be stamped out as in Fig. 4, and provided at opposite edges with staggered teeth J', which will press back the rubber and thread their way into the softened walls of the perforations C,

thus serving the same purpose as the form shown in Fig. 2. I have also found that my process serves equally well with perforations extending only part way through the softenable body as shown in Fig. 5, in which K is a perforation entering the body from one side and L is a metal member inserted into a corresponding opening on the other Side of the plug M. Consequently, my method will serve equally well for making the desired projections singly or in oppositely disposed pairs.

I have also found that the method of my invention will serve equally for forming raised metal projections upon sheets of insulatin material, as shown in Fig. 8, in which [Il is a plate of hardrubber and O is a metal switch pivot inserted in the same by my process. In thus securing metal projection-forming members to sheets or plates, itis not necessary to soak the lwhole plate in hot water, as the softening influence may be employed in the form of a jet of hotwater or steam sprayed upon the portions of j the plate ory sheet adjacent to the perforation in which the metal member is to be inserted. Where a number of such metal rojections are thus united with a single p ate, as in the making contacts for a rheostat, the whole group of projections may be trimmed down to the desired height simultaneously by means of a grinding isk.

Where the projections areo positely disiosed as in the attachment p ug shown in atent No. 1026269 granted to me May 14,

1912, I preferably trim both of the projections slmultaneously to the desired height by restlng the rubber body in the socket portion of d1e P, as shown in Fig. 10, and cutting ofi' the surplus length of the inserted projectionformin member D with a die R.

It wi l be obvious from the above that the extent tov which the projection-forming material projects above the material into which it is anchored, can readily be determined with accuracyand uniformity; that where tiaasao such projections are to be. oppositely disposed, the distance between the tips of the opposite projections can be accurately predetermined; and that the projection-forniing material will be so firmly anchored as not to permit of any change in the dimensions thus determined.

I am aware that such projections have heretofore been produced by driving or twisting a bar through an orifice into which it fits tightly. But I have found in practice that it is difficult to stop the inserted bar at the exact points corresponding to the desired projection of the bar, and that even when thus stopped, the bar will slide to and fro later on so as to vary the distance to which it projects. By starting with a surplus length of the inserted material, I avoid the need of 'great exactness in stopping it at the right point and make it an easy matter to obtain any desired amount of projection.

I am aware that threaded members have heretofore been anchored in wood or similar moisture-absorptive materials by softening the wood with a liquid, such as a solvent of glue, inserting the threaded member while the wood is thus softened and therefore yielding, and permitting the softened and glue-saturated wood to harden. However, such a process could only be used with materials like wood which will absorb moisture, and the resulting anchoring of the inserted memberwas dependent upon the action of the adhesive carried by the solvent. IConsequently, this older process is not applicable with amorphous and non-moisture-absorbtive materials, such as hard rubber.

While I have illustrated and described my process as applied to the producing of metal projections upon hard rubber, and as uslng steam or hot water as the' softening influences, it will be evident that my process will be applicable also to other materlals and that softening influences other than water or steam may be used in the process; also that my process is articularly applicable to amorphous materlals which are normally unyieldlng and incomprehenssible. It will also be evident that the above described method of anchoring inserted parts in a softenable material may be used for other purposes than the forming of projections, but I do member composed of an amorphous, normally unyieldingv and non-molsture-absorptive material without the use of an adhesive, which consists in perforating the member Ill tening influence and having an excess of length by which it may be manipulated for insertion; allowing lthe softened and compressed portion of the perforated member to harden and anchor the inserted member by pressure upon the latter; and cutting off the exposed surplus length of the said inserted member. i

2. The method of forming oppositely disposed immovable ,projections of predetermined heights upon a member composed of a normally unyielding material, which consists in perforating the member along the common axis upon which the desired .projections are to be located; subjecting .the member to a heating and softening iniuence until the wall of the perforation is sulficiently softened to render the same yielding; inserting into the perforation while its wall is in the said yielding state 4a member composed of a material which is normallyl unyielding and which isl unaffected by the said softening influence, the said inserted member having raised portions adapted to compress the softened wall of the perforation while being inserted; the said inserted member being greater in length than the distance between the tips of the desired projections, be manipulated for insertion; allowing the softened and compressed wall of the perforation to harden; and cutting olf the exposed surplus length of the inserted material.

3. The method of forming oppositely disposed immovable projections of predeterminedheights upon a member composed of a normally unyielding material, which consists in perforating the member along the common axis upon which the desired projections are to be located; subjecting the member to a heating and softening inliuence vuntil the wall of the perforation is sufficiently softened to lrender the same yielding; screwing into the perforation (while its wall is in the said yielding state) a member composed of a material unaffected by the said softening influence, the said latter member having upon a portion of its length raised threads adapted to compress they softened wall of the perforation while being inserted; the said inserted member being greater yin length than the distance between the tips of the desired projections7 the excess in length enabling it to be manipulated for insertion; allowing the softened and compressed wall of the perforation to harden; and cutting off the exposed surplus length of the inserted material.

GEO. C. KNAUFF.

Witnesses: i

CARL L. OTREMBA,

GERALD G. BARRY.

the excess in length enabling it to 

